PEM fuel cells, also known as polymer electrolyte membrane fuel cells (PEMFC), are a type of fuel cell being developed for transport applications as well as for stationary and portable applications. Their distinguishing features include lower temperature/pressure ranges and a special polymer electrolyte membrane. A PEM fuel cell transforms the chemical energy liberated during the electrochemical reaction of hydrogen and oxygen to electrical energy, as opposed to the direct combustion of hydrogen and oxygen gases to produce thermal energy.
A stream of hydrogen is delivered to an anode side of the PEM fuel cell. At the anode side it is catalytically split into protons and electrons. This oxidation half-fuel cell reaction is represented by:H22H++2e−
The newly formed protons permeate through the polymer electrolyte membrane to the cathode side. The electrons travel along an external load circuit to the cathode side of the PEM fuel cell, thus creating the current output of the fuel cell.
Meanwhile, a stream of oxygen is delivered to a cathode side of the PEM. At the cathode side oxygen molecules react with the protons permeating through the polymer electrolyte membrane and the electrons arriving through the external circuit to form water molecules. This reduction half-fuel cell reaction is represented by:4H++4e−+O22H2O
A PEM fuel cell is an energy conversion device that combines a fuel (e.g., hydrogen) and air to directly produce electrical power. PEM Fuel cells can offer high efficiency and low emissions when compared to conventional technologies. Unlike internal combustion generators, fuel cells convert chemical energy directly into electricity without an intermediate conversion into mechanical power. If pure hydrogen is used as a fuel, the only, products of this process are heat, electricity, and water.